Question 647476
Let m be Michelle's age.
Let j be Josh's age.

m = j+8<---
m-3 = 2*(j-3)

Solve the 2nd equation

m = 2j - 6 + 3

m = 2j -3 <----

Set the two arrowed expressions equal to each other.

j+8 = 2j-3

-j = -11

j = 11

If j =11 then  Michelle is (11+8) or 19 years old.